The simplest method is to move the .thunderbird folder onto the new
drive
and link to it from the system drive. The not-so-simple method is to copy
out the particular folder and move it into .thunderbird. Or maybe to go
into .thunderbird on the system drive and make a symlink *inside that
folder* to the e-mail accounts folder on the new drive. Maybe I'll try
that. You can be sure I'll back everything up--I'm getting a portable HDD
with 4 TB of capacity that I'm going to use as an all-around system backup.
On rebuild I did a first time start of Thunderbird for the user so it
creates the users [abcdefgh].default file in /home/user/.thunderbird, at
which time I reloaded the add-on etc. etc. but canceled signing into any
account or setting up any such. Purpose was simply to accomplish two
things 1) load any add-on such as lighting and 2) was to create the
[abcdefgh].default file in /home/user/.thunderbird. Once this was done
/then/ I removed the existing /home/user/.thunderbird directory and linked
the /Crypt/user/.thunderbird directory on the "Crypt" drive. Start
Thunderbird again and it will check compatibility of add-on and then
everything should look/work the way it did before the rebuild. Thunderbird
will see the older [stuvwxyz].default file and operate as if nothing
changed. Life saver given how I had everything set up and my filters
were... a lot. Go through your accounts (check for mail) and ensure all
the log-in function.